Background:
Demand for video telemetry (VT) is increasing but most departments have limited capacity for the investigation so waiting times can be long. Ambulatory EEG offers a cheaper more flexible alternative for long term EEG monitoring but until recently has been hindered by the lack of synchronised video which is essential for the diagnosis of many conditions. Home Video Telemetry (HVT) using standard EEG recording equipment has been shown to be a cost-effective alternative to in-patient video telemetry (IPVT)1. HVT using recently developed commercially available ambulatory EEG systems with synchronised video may offer a more practical alternative.
Aim
To compare HVT (using ambulatory EEG with synchronised video) to IPVT in terms of:
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Diagnostic efficacy
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Quality of recording
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Acceptability to patients
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Amount of technical time required
Methods
A pro-forma was completed for 41 HVT and 76 IPVT adult patients under investigation. Patients were investigated either to diagnose attacks (epileptic, non-epileptic or parasomnias) or to obtain polysomnography (PSG) prior to MSLT. Patients undergoing VT for pre-surgical evaluations were excluded. Information was obtained from all patients on the number of attacks recorded, whether the diagnostic question was answered by the VT, the quality of video and EEG recording and whether their preference was for investigation in their home or hospital. For the HVT group, the patient’s views on the ease of the procedure and the amount of extra technical time required to perform HVT were noted. Fisher’s exact test was used for statistical analysis.
Results
83% (34) of HVT and 73% (62) of IPVT patients were investigated to record undiagnosed attacks. The remaining patients were investigated with polysomnography to aid interpretation of the following day’s MSLT.
Of the patients experiencing attacks, 74% (25/34) of HVT patients had typical clinical attacks during HVT compared to 63% (39/62) during IPVT (n.s.). All pre-MSLT PSGs were useful in interpreting the MSLTs. The diagnostic question was answered in 76% (31/41) following HVT and 70% (53/76) following IPVT (n.s.).
There was no significant difference between quality of EEG video recording during the attacks with all attacks seen clearly on video in 76% (19/25) of HVT and 74% (29/39) of IPVT. Neither was there any difference in night time video quality which was satisfactory in 85% (35/41) of HVT and 93% (71/76) of IPVT. Quality of EEG recording was satisfactory in 97% (40/41) of HVT and 91% (69/76) of IPVT (n.s.).
4 patients (10%) reported some difficulty using the HVT equipment but diagnostic information was only lost in one of these patients. After completion of the investigation, 2 (5%) HVT patients said they would have preferred hospital investigation whereas 33 (43%) of IPVT patients would have preferred home investigation. Extra technical time for home visits (mean 2 hours) was given for the first 7 patients but subsequent patients did not require these.
Conclusion
HVT with video-ambulatory EEG offers a convenient and economical alternative to IPVT. It provides results of similar quality and diagnostic efficiency, is acceptable to patients and does not necessarily require additional technical time.
